International Society for Photogrammetry and Remote Sensing

1
International Society for Photogrammetry and
Remote Sensing ISPRS Commission VI Workshop, Dar
es Salaam, Tanzania, 25-28 March 2002 MAPPING
IMAGING AFRICA ON THE INTERNET Mike Shand
Department of Geography Topographic
Science University of Glasgow mshand_at_geog.gla.ac
.uk
http//www.geog.gla.ac.uk/mshand/
2
OVERVIEW
The Internet is awash with a wealth of maps and
spatial imagery, some crude and basic, some
refined and highly developed. With increasing
internet access and faster bandwidths, Africa is
well-placed to benefit from Internet Mapping
technology. There are three possible options for
delivering and viewing maps and imagery over the
Internet static, animated and interactive. This
paper will review and illustrate current Internet
Mapping technology utilising example maps and
images of Africa and in particular Tanzania.
3
Internet Connectivity in Africa
The Internet is unevenly distributed between and
within countries in Africa. South Africa (55)
together with the North African countries of
Egypt, Morocco, Tunisia and Algeria account for
75 of total subscribers in Africa.
4
Internet Developments in Africa
PROBLEMS Average of 1 phone line per 50 persons
in Africa (in East and West central Africa
1350) Elderly analogue communications subject
to power irregularities. Slow connectivity
speeds and high costs are common resulting in
overseas hosting of many Africa web sites and
e-mail servers in USA and Europe.
SOLUTIONS Satellite, digital, cellular and fibre
optic telecommunications technology now being
recognised and adopted at government level in
Africa. New fibre optic ring around Africa due
in 2002 with world wide links. East African
Co-operation (EAC) project established to install
fibre optic backbone between Dar es Salaam,
Nairobi and Kampala.
5
African Maps Imagery on the Internet
MAP USES ON WEB SITES Geographical location,
route-finding, illustration and map servers
MAP USERS ON WEB SITES Private companies and
businesses (e.g. travel, transport,
commerce) Education establishments and
researchers News and weather services Governmen
t and non-government organisations
6
African Maps Imagery on the Internet
MAP USES ON WEB SITES
Extract from the newafrica.com web site offering
an extensive set of maps to view, print or
download.
7
African Maps Imagery on the Internet
MAP USES ON WEB SITES
Example of basic maps used to enhance a web site.
8
African Maps Imagery on the Internet
DEDICATED MAP SERVER WEB SITES
Example of small-scale mapping supplied free over
the Internet.
9
African Maps Imagery on the Internet
DEDICATED MAP SERVER WEB SITES
Online ordering from Surveys Mapping, South
Africa
10
African Maps Imagery on the Internet
DEDICATED MAP SERVER WEB SITES
A dedicated map site hosted by the USGS offering
online maps and data
11
Internet Mapping Technology
FILE FORMATS USED ON THE INTERNET Raster and
Vector JPEG GIF PNG TIFF - PDF
FLA SVG VRML
Raster Zooming
Vector Zooming
12
How to Create and View Maps Imagery on the
Internet
MAPPING AND IMAGING OPTIONS Static mapping
sites allow the user to access fixed raster map
data or remotely sensed images to view or
download. Animated mapping
sites allow the user to view raster or vector
maps or imagery dynamically as the content
changes. Interactive mapping sites allow the
user to zoom or pan high resolution raster or
vector maps and images and to make decisions on
content or design.
13
How to Create and View Maps Imagery on the
Internet
MAPPING AND IMAGING OPTIONS
Static mapping sites allow the user to access
fixed raster map data or remotely sensed images
to view or download.
14
How to Create and View Maps Imagery on the
Internet
STATIC MAPS IMAGERY
Static Maps and Imagery can be created by RASTER
SCANNING or FILE CONVERSION Two raster file
formats are currently used for direct viewing of
maps and imagery on Internet Browsers GIF (.gif)
and JPEG (.jpg .jpeg) Static raster GIF or JPEG
files cannot be zoomed or edited from within
browsers such as Netscape or Internet Explorer.
15
How to Create and View Maps Imagery on the
Internet
STATIC MAPS IMAGERY
RASTER SCANNING
Advantages ease of use and availability image
manipulation possible before uploading
Disadvantages file size / resolution
conflict high resolutionlarge file slow
download times
Unfortunately there are more bad examples of
raster scanned maps than good ones on world wide
web sites
16
How to Create and View Maps Imagery on the
Internet
STATIC MAPS IMAGERY
FILE CONVERSION
Vector to raster file conversion can be
accomplished directly from within vector GIS,
mapping or graphics software (e.g. ArcView
MapInfo Adobe Illustrator Macromedia Freehand
CorelDraw), or indirectly with intermediate
software (e.g. Adobe Photoshop Paintshop
ProCorel Photo-Paint) or via file conversion
utilities (e.g. GraphicConvertor
GIFConvertor). Most GIS, mapping and graphics
software now offer a web option for file export
and conversion to web compatible formats.
17
How to Create and View Maps Imagery on the
Internet
ANIMATED MAPS IMAGERY
Animated mapping sites allow the user to view
raster or vector maps or imagery dynamically as
the content changes.
18
How to Create and View Maps Imagery on the
Internet
ANIMATED MAPS IMAGERY
Animated Maps and Imagery can be created
from vector maps or raster imagery using
multiple image file formats (Flash, GIF89a ,
MPEG) or by delayed refresh of screen maps
. Animated maps can be created from vector maps
produced in graphics software packages (eg
Illustrator, Freehand, CorelDraw) by saving each
map layer as a separate raster file (GIF or
JPEG). Animated imagery can be created simply by
overlaying a series of matching air photos or
satellite images.
19
How to Create and View Maps Imagery on the
Internet
ANIMATED MAPS IMAGERY
Gif89a format allows multiple images to be
included in one file
20
How to Create and View Maps Imagery on the
Internet
INTERACTIVE MAPS IMAGERY
Interactive mapping sites allow the user to zoom
or pan high resolution raster or vector maps and
images and to make decisions on content or design.
21
How to Create and View Maps Imagery on the
Internet
INTERACTIVE MAPS IMAGERY
can be created with vector or raster mapping, GIS
and imaging software. Mapping plug-ins include
Macromedia Flash, Shockwave and Adobe Acrobat.
GIS plug-ins include Autodesk Mapguide,
Intergraph Geomedia Web Map, ESRI Internet Map
Server, and Dataview Solutions Pavan
web.Publisher. Imagery is best viewed in
specialist file compression plug-ins such as
Lizardtech Mr SID or ERMapper ECW. Access to
file databases can also be by user entry to
SUBMITTED FORMS or directly via browser or
client/server PLUG-INS, Applets, and Javascripts.
22
How to Create and View Maps Imagery on the
Internet
INTERACTIVE MAPS IMAGERY
Interactive maps or imagery (raster or vector)
can be viewed by user query of a database via
keyboard to a submitted form. This allows the
user to make decisions on content or design.
23
How to Create and View Maps Imagery on the
Internet
INTERACTIVE MAPS IMAGERY
Interactive vector maps can be viewed, zoomed and
queried by the use of browser plug-ins at high
resolutions and large zoom factors without loss
of quality Mapping PLUG-INS include Adobe
Acrobat and Macromedia Flash/ Shockwave. GIS
browser PLUG-INS include Autodesk MapGuide ESRI
Geomedia Web Server. Imagery and scanned map
browser PLUG-INS include Lizardtech MrSID and
ERMapper ECW.
24
How to Create and View Maps Imagery on the
Internet
Example of the vector PLUG-IN from Adobe Acrobat.
25
How to Create and View Maps Imagery on the
Internet
Example of the vector PLUG-IN from Macromedia
Shockwave.
26
How to Create and View Maps Imagery on the
Internet
Example of the vector GIS viewing PLUG-IN from
ESRI MapObjects.
27
How to Create and View Maps Imagery on the
Internet
Example of the vector GIS PLUG-IN from Autodesk
MapGuide.
28
How to Create and View Maps Imagery on the
Internet
Example of the Mr SID viewer interface from
Lizardtech.
29
How to Create and View Maps Imagery on the
Internet
Example of the ECW viewer interface from ERMapper.
30
MAPPING IMAGING AFRICA ON THE INTERNET
Conclusion
The Internet has created a new medium for maps
and spatial data, the Mapping Industry must rise
to the new technology of Web Cartography. Researc
h and guidelines should be developed to ensure
quality web map design. Internet map technology
is moving fast and will not stand still. Users
will demand faster web distribution and more
online interaction. New developments include
devices with Internet access such as PDAs, WAP
phones, GPS and XML / GML enabled laptops and
in-car computing. The real challenge for Africa
if it wishes to participate in the Internet
mapping revolution is to make available
up-to-date topographic maps at national level in
fully structured digital and GIS compatible
formats.
31
MAPPING IMAGING AFRICA ON THE INTERNET
Further Information
Further web mapping information including
free ONLINE WEB MAPPING WORKSHOPS can be found
at Mike Shand Mapping the Web Workshop
http//www.geog.gla.ac.uk/mshand/Thompson2000/ww
w2000/webtitle.htm ITC Web Cartography
developments and prospects http//kartoweb.itc.nl
/webcartography/webbook/index1.htm Mike
Peterson, ICA Commission on Maps and the Internet
http//maps.unomaha.edu/ICA/Maps26Internet/Resea
rch/Questions.html